Looking for a way to add letterboxes to a video in either Ubuntu or WinXP?

I’m really fond of watching videos on my ipod, every morning i have to stay about twenty minutes on a subway train to get to my university and a video from thatguywiththeglasses is generally my pick to pass the time, the problem is that, even though i can convert them alright, most of them (expecially the new ones) are widescreen and i can’t seem to find a program that, instead of cropping or fitting the image simply adds letterboxes. The same goes for most movies, which are practically always widescreen.

I found a tutorial on how to do so with ffmpeg but after a hour and a half of trying to get the bastard to run i finally decided it wasn’t worth the effort and quit.

All i need is a program that allows me to add a letterbox to a video in order to fit another aspect ratio, so i can watch my 16:9 videos on my 4:3 ipod screen, and doesn’t need you to be a video editing genius to run it. I’m fairly good with computers but video editing/encoding has never been my strong suit.